Digital video compression finds wide application in a variety of devices including televisions, smartphones, personal computers, laptops, cameras and video conferencing. Where video compression is used, such devices implement video compression encoding and decoding as defined in standards such as HEVC (High Efficiency Video Coding) and H.264.
The standards set out that video frames are to be divided into rectangular picture regions known as blocks. Each video frame is divided into coding tree units (CTUs) which are processed in raster scan order. Each CTU is sub-divided into multiple sub-blocks and divided again as permitted by H.264 and HEVC.
In order to achieve good performance, the standards require that a decoder retains information from previously decoded blocks in the same frame. Typically, a decoder makes calculations or decisions based on values or attributes of neighbouring blocks that have already been decoded.
Video image data is commonly processed by spatially segmenting frames into tiles or slices which can be decoded independently of other slices or tiles.
Aspects and embodiments were conceived with the foregoing in mind.